# 3,4-DIHYDROXY-THIOPHENE-2,5-DICARBOXYLIC ACID DIETHYL ESTER (CAS 1822-66-8) CAS: 1822-66-8 PubChem CID: 245503 InChIKey: YOKOBAHUBJPMGP-UHFFFAOYSA-N Molecular formula: C10H12O6S Molar mass: 260.27 g/mol IUPAC: diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate SMILES: CCOC(=O)C1=C(C(=C(S1)C(=O)OCC)O)O InChI: InChI=1S/C10H12O6S/c1-3-15-9(13)7-5(11)6(12)8(17-7)10(14)16-4-2/h11-12H,3-4H2,1-2H3 logP (XLogP3): 3.1 PSA: 121 A^2 Hydrogen bond donors: 2 Hydrogen bond acceptors: 7 Rotatable bonds: 6 Heavy atoms: 17 ## About the compound 3,4-DIHYDROXY-THIOPHENE-2,5-DICARBOXYLIC ACID DIETHYL ESTER (CAS 1822-66-8) is a chemical compound registered under CAS number 1822-66-8. Molecular formula: C10H12O6S. Molar mass: 260.27 g/mol. The full systematic IUPAC name is: diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate. Chemical data comes from the PubChem (NIH), ChEMBL (EBI) and NIST WebBook databases. GHS statement translations comply with the CLP Regulation (EC 1272/2008). Interactive 3D model and 2D skeleton available at: https://molgod.org/molekula/1822-66-8/ ## GHS classification Signal word: Warning Pictograms: GHS07 Hazard statements (H): H315: Causes skin irritation H319: Causes serious eye irritation H335: May cause respiratory irritation Precautionary statements (P): P261: Avoid breathing dust/fume/gas/mist/vapours/spray ## Available in the shop Shop: MolGod Product: 3,4-DIHYDROXY-THIOPHENE-2,5-DICARBOXYLIC ACID DIETHYL ESTER (CAS 1822-66-8) — Beijing Tong Guang URL: https://molgod.org/sds-cards/34-dihydroxy-thiophene-25-dicarboxylic-acid-diethyl-ester-cas-1822-66-8-beijing-tong-guang/ ## Regulatory compliance checklist Status based on: ADR 2025 (Table A), REACH Annex XVII, CLP Annex VI (harmonised classification), hazard class from the m14-spill DB, SVHC, GIS and the Polish OEL list. Principle: no data = no claim (we do NOT declare "no restrictions" without a basis). 4 required / 12 items [required] SDS (Safety Data Sheet) available (sds) How to comply: Requirement: current SDS compliant with Reg. 1907/2006 (REACH) Annex II, 16-section format. Source / form: https://echa.europa.eu/information-on-chemicals [required] Compliant CLP label (pictograms + signal word + H/P) (clp_label) How to comply: The label must include: GHS pictograms, the signal word (Danger/Warning), hazard (H) and precautionary (P) statements, and manufacturer details. Required since 2010 (substances) and 2015 (mixtures). Source / form: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008R1272 [required] Chemical OSH training (substance-specific) (bhp_training) How to comply: Laboratory staff: initial training (general induction + job-specific) + refresher training every 5 years (or every 3 for engineering/technical positions). Documentation kept in personnel files. Source / form: https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20040180169 [not applicable] BDO registration (Polish Waste Database) (bdo_registration) How to comply: The verified GHS classification does not indicate classes resulting in hazardous waste — BDO registration for this substance is not required. Verify the EWC code for the specific waste form. Source / form: https://bdo.mos.gov.pl/ [to be verified] ADR transport (international agreement) (adr_transport) How to comply: No ADR data in the MOL-GOD dataset for this CAS number. Do NOT assume there are no restrictions — before shipping, verify the transport classification in ADR 2025 (Table A) and in section 14 of the safety data sheet (SDS). Source / form: https://unece.org/transport/dangerous-goods/adr-2025-files [conditional] REACH registration (>1 t/year EU import) (reach_registration) How to comply: Importers/manufacturers ≥1 tonne/year must register the substance with ECHA (technical dossier + Chemical Safety Report if ≥10 t). Check the ECHA Annex VI / registered substances list. Source / form: https://echa.europa.eu/regulations/reach/registration [to be verified] SVHC notification (Substances of Very High Concern) (svhc_declaration) How to comply: SVHC status not verified against the available dataset — check the current ECHA candidate list; do not assume the absence of an entry. Source / form: https://echa.europa.eu/candidate-list-table [to be verified] REACH Annex XIV (authorisation list) (reach_annex_xiv) How to comply: Not verified against the ECHA Authorisation List — check REACH Annex XIV. Source / form: https://echa.europa.eu/authorisation-list [to be verified] REACH Annex XVII (use/marketing restrictions) (reach_annex_xvii) Source / form: https://echa.europa.eu/substances-restricted-under-reach [to be verified] OEL — Occupational Exposure Limit in the working environment (nds_workplace) How to comply: No NDS data in the MOL-GOD dataset (incomplete set — ~41 of ~600 substances in the list). Absence does NOT mean there is no NDS — check the full list in Dz.U. 2024 poz. 1017 (Regulation of the Ministry of Family and Social Policy of 4 September 2024), and where none exists apply the OEL from EU directives or values recommended by NIOSH/ACGIH. Source / form: https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20240001017 [to be verified] GIS register (precursors / psychotropics) (gis_register) How to comply: Does not appear in the available working set of precursors (list incomplete). Absence is NOT a confirmation — verify against Annex I of Reg. (EC) 273/2004 and the GIS list before placing on the market. Source / form: https://www.gov.pl/web/gis [required] Safety Data Sheet in Polish (sds_pl) How to comply: Requirement: SDS in Polish for trade in PL (Art. 31 REACH + Chemical Substances Act Art. 17). Source / form: https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20012112135 ## Data sources - PubChem CID 245503: https://pubchem.ncbi.nlm.nih.gov/compound/245503 - NIST WebBook: https://webbook.nist.gov/cgi/cbook.cgi?ID=1822-66-8 - ChEMBL: https://www.ebi.ac.uk/chembl/g/#search_results/all/query=1822-66-8 --- Standalone HTML page: https://molgod.org/molekula/1822-66-8/ Markdown version: https://molgod.org/molekula/1822-66-8.md JSON API: https://molgod.org/wp-json/molgod/v1/molecule/1822-66-8 Last updated: 2026-09-02 Generator: MOL-GOD v3.12.33